EGL Ref: 9215 23 June 2022 Page 44 This report shall only be read in its entirety. File: WAI-985-000-REP-LC-0002_Rev0.docx. these risks underdrainage and a large perimeter embankment would need to be constructed. 8.0 POTENTIAL LOCATIONS FOR EXPANSION OF TAILINGS STORAGE AND ROCK DISPOSAL Potential locations for tailings storage and rock disposal are described and discussed in the sections below. The locations of the existing TSFs (Storage 2 and Storage 1A) and stockpiles are shown in Figure 31. The locations of other potential tailings storage and mine overburden disposal sites are shown in Figure 32. 8.1. Existing Storage 2 site Raising the existing Storage 2 TSF embankments can provide storage for additional tailings and mine open pit overburden material as follows: • Raising of Storage 2 for increased tailings storage. • Open pit mine overburden material can be used to raise the existing Storage 2 embankment. • Storage 2 can be raised by downstream or centreline construction. Downstream construction can provide a significant increase in storage if it was extended beyond the downstream toe of the existing embankment. A major constraint is that it would not meet the project scheduling requirements because it would require a large volume of fill and would require removal of the existing outer capping layers (Zones G and H), removal and re-siting of the perimeter road and access to the Processing Plant, and removal and reconstruction of the perimeter drain, collection and silt ponds, the seepage/leachate collection system. A small downstream construction raise by steepening of the downstream shoulder above existing higher level benches is an option. A small centreline raise constructed above existing higher level intermediate benches is also an option. • Dry stacked filtered tailings could be placed above the existing tailings without any raise of the Storage 2 embankment. However, this option is not suited to the climate at Waihi. Capital and operating costs are very high. • Mine open pit overburden material could be placed above the existing tailings to create a dry cap. This would compromise future raising to provide additional tailings storage and a dry cap is not considered the best closure option. 8.2. Existing Storage 1A site Raising the existing Storage 1A TSF embankments can provide storage for additional tailings and mine open pit overburden material as follows: • Raising of Storage 1A for increased tailings storage. • Open pit mine overburden material can be used to raise the existing Storage 1A embankment. Downstream construction can provide a significant increase in storage if it was extended beyond the downstream toe of the existing embankment. A major constraint is that it would not meet the project scheduling requirements because it would require a large volume of fill and require removal of the existing outer capping layers (Zones G and
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